b. The deep-sea 



c. Oligotrophic open-ocean gyres 



d. The top 10 cm of the water column 



e. The near-bottom nepheloid layer 



f. The interstitial water of sediments. 



Synthetic Organic Materials — Synthetic organic chemicals are sub- 

 stances produced from naturally occurring raw materials. They usually 

 do not occur in nature, and are developed and produced for some chemi- 

 cal or physical property that makes them useful, or they are produced 

 as by products. 



The wide variety of plastics, synthetic fibers, and pesticides, such 

 as the chlorinated hydrocarbon DDT and polychlorinated biphenyls 

 are examples. Several hundred synthetic organic chemicals are being 

 produced in multi-ton quantities (see Table 6). 



In the manufacture, transportation and use of these materials a prob- 

 ably substantial, but unknown, fraction of the total is injected into the 

 marine environment. Life processes have an impact on these materials 

 and vice versa. In some cases they are biologically degraded, which 

 can be useful in the disposal of unwanted substances. Because of their 

 solubility in lipids, they may become more concentrated in organs and 

 organisms as the trophic levels are ascended. It has become evident 

 during the past few years that some of these synthetic chemicals have 

 an impact on marine life that constitutes a potentially serious threat. 

 Several recent workshops have drawn attention to this problem and 

 suggested plans for major research efforts to evaluate their impact 

 (SCEP, 1970; Ketchum, 1972; and National Academy of Science, 

 1971, b). 



We are in a strong position to formulate and carry out specific research 

 directed at specific problems. Several pollutants of global concern 

 have been identified. DDT and its decomposition products and poly- 

 chlorinated biphenyls are examples. Others may be identified. The 

 factors that combine to yield a potentially significant pollutant are: 

 high production rates by industry; resistance to degradation in the 

 environment; a route of transfer such as atmospheric transport from 

 source to site; significant biological uptake; and toxicity for some 

 level of life. These factors also allow a research program to be defined. 

 At the present time the research needs are as follows: 



1. Measurements of the levels of suspected toxic materials should 

 be made in water, biota, and sediments. This research may require only 

 local studies for some pollutants, or it may need global studies for 

 pollutants such as DDT and the PCBs. Analytical methods are available 

 for such research. 



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